I have your GSM Shield.
I power the unit stand alone and have 4.2V on VBat. The unit registers on the network.
PC comms set at 19200,8,N,1 connected via header J17 of the GSM. I do a rx-tx loop back test at D7-D8 and it’s fine, But I can not get the GSM to accept AT Commands.
Any ideas ???
Thanks for purchasing our product.
I suggest you to first to following our wiki instructions: garden.seeedstudio.com/index.php … PRS_Shield
rx-tx of J17 is the rx-tx of the Sim900, so RX of J17 should connect to other device’s TX, and TX of J17 should connect to other device’s RX
